1. Field of the Invention
The present invention relates to multi-way connectors for electrical circuitry and is concerned in particular with the provision of a removable filter array in such multi-way connectors.
2. General Background of the Invention
In the provision of filter devices to suppress interference on signal and power lines, there are substantial advantages to be gained if the devices can be reliably incorporated within the confines of a multi-way connector. Not only does this utilise space most economically, but the filters have the shortest and therefore potentially the least impedance ground return path to provide the optimum filtering characteristics at high frequencies. This potential is only fully realised if the filters are grounded with a low resistance contact. The filters themselves should be protected from the environment and also from mechanical stresses imposed via the contact when the connector is mated and also via the rear terminations when the connector is soldered or otherwise connected to external circuitry.
It is known to incorporate a plurality of filter devices within a multi-way connector, using a ground plane in the form of a metal plate which has a plurality of through holes, each of which contains a respective annular filter capacitor whose outer electrode is soldered to the metal ground plane which is itself connected electrically and rigidly fixed to a metal outer casing of the connector. Each annular filter capacitor embraces and is soldered to a respective lead-through termination.
One problem with this known structure is that if any one of the filter capacitors breaks down or otherwise fails in use, then the whole connector becomes useless and must be discarded and replaced. This arises due to the fact that, once assembled, it is not practicable to dismantle the connector for repair purposes.
The same problem arises in embodiments where, instead of discrete discoidal annular filter capacitors, a planar array of capacitors is formed by a multilayer disc of ceramic having metal layers incorporated therewithin to form the capacitor electrodes, the multilayer structure having a plurality of axial holes connected to internal metal electrodes and soldered directly to connector pins inserted in the holes, with one common internal electrode forming an earth plane and being exposed at the periphery of the multilayer structure where it contacts the outer metal shell of the connector.